Vibration isolating electrode mount



June 16, 1964 R. J. NEY ETAL 3,137,803

VIBRATION ISOLATING ELECTRODE MOUNT Filed Sept. 22, 1961 2 Sheets-Sheetl INVENTO'RS: ROBERT J. NEY, DONALD L. SCHAEFER',

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THEI TTORNEY June 16, 1964 R. J. NEY ETAL 3,137,803

VIBRATION ISOLATING ELECTRODE MOUNT 'INVENTORS: ROBERT J. NEY, DONALD L.SCHAEFER,

BY THE/@%TTORNEY. I

United States Patent,

3,137,803 VIBRATION ISOLATING ELECTRGDE MOUNT Robert J. Ney, Mattydale,and Donald L. Schaefer, Camillus, N.Y., assignors to General ElectricCompany, a corporation of New York Filed Sept. 22, 1961, Ser. No.139,910 Claims. (Cl. 313-67) The present invention relates toimprovements in camera tubes, such as those of the image orthicon type,wherein a charge pattern representative of an optical image is formed ona thin membrane-like charge storage target which may cooperate with anadjacent foraminate or mesh-like electron collector electrode. As iswell known to those skilled in the art, in the operation of a cameratube of the image orthicon type, light falling on the photo-emissivesurface of the tube produces emission of electrons which are acceleratedaxially toward, and impinge upon, a transversely extending chargestorage target. The primary electrons arriving at the charge storagetarget produce emission of secondary electrons which are collected by aclosely spaced confronting foraminate or mesh-like electron collectorelectrode so as to leave a charge pattern on the storage target which isrepresentative of the optical image supplied to the photo-sensitivesurface of the tube. The stored information is read out as modulation ofthe return current of an electron beam which scans the charge storagetarget.

In such a camera tube any relative motion between the charge storagetarget and the adjacent electron collector mesh electrode has a severelyadverse effect on the quality of a picture or image reproducable fromthe signal read out from the tube. Such relative motion usually shows upin the reproduced picture as microphonic bar patterns, which of courseseverely impair the fidelity of the resulting picture. Moreover thetarget and mesh electrode are frequently supported drum-head fashionexclusively from an annular peripheral frame and hence are susceptibleto relative movement toward and away from one another when the tube issubject to vibration at frequencies approaching any of the resonantfrequencies of the target or collector electrode.

Accordingly, it is a principal object of the present invention toprovide an improved vibration-isolating mounting means for the targetand collector electrode assembly of a camera tube of the foregoingcharacter, such as to minimize movement of the charge storage targetrelative to the collector electrode.

Another object is to provide an improved vibrationdamping mounting meansfor an image orthicon target or the like which provides effectiveruggedization against severe environmental conditions of vibration, andenables attainment of acceptable picture quality under vibrationalconditions which have heretofore completely prec'luded satisfactory tubeoperation.

Another object is to provide a vibration-damping mount for targetcollector electrode assemblies and the like which insures substantialattenuation of vibration at frequencies equal to and above also belowthe resonant frequencies of the target and collector electrode, butpermits sufficient movement of the target and collector electrode atfrequencies below their resonant frequencies so as to avoid rupture orother shock damage to the target or collector electrode.

Another object is to provide such a vibration isolating mount which ismechanically simple, inexpensive, durable, and easy to install.

Another object is to provide such a vibration-isolating mount fabricatedfrom materials which are not detrimental to the high vacuum environmentof an electron tube.

These and other objects of the invention will be apparent from thefollowing description and the accompanying drawings, wherein:

FIGURE 1 is an axial sectional view of the image portion of an imageorthicon type of camera tube constructed according to the presentinvention;

FIGURE 2 is a transverse partially broken away sectional view of thestructure of FIGURE 1 taken on the line 2-2 thereof;

FIGURE 3 is an enlarged fragmentary sectional view of a portion of thestructure of FIGURE 2 taken on the line 33 thereof;

FIGURE 4 is an enlarged fragmentary sectional View of a portion of thestructure of FIGURE 2 taken on the line 4-4 thereof; and

FIGURE 5 is an enlarged fragmentary perspective View of a portion of thestructure of FIGURE 2.

Referring to the drawings and particularly to FIG- URES 1 and 2 thereof,there is shown a portion of a camera tube of the image orthicon typeincluding an evacuated envelope 2 having at its front end a viewingwindow 4 on the interior surface of which is a photosensitive layer 6.Responsive to a light image falling on the layer 6, electrons areemitted therefrom and are accelerated axially or longitudinally by anannular accelerating electrode 8, and an annular target cup electrode 10to a transverse planar membrane-like electric charge storage target 12.The primary electrons hitting the charge storage target 12 produceemission of secondary electrons which are collected by a meshlikeelectron collector electrode 14 disposed in closely spaced confrontingrelation with the forward face of the target 12. A charge pattern isthus formed on the charge storage target representative of the lightimage falling on the photo emissive layer 6.

' The target-collector electrode assembly 16 includes an annularsupporting frame 18 across which the collector mesh 14 and the target 12are stretched drumhead fashion in spaced relation. The acceleratingelectrode 8 and target cup electrode 10 are connected by insulatingmembers 20 and are firmly supported from the interior surface ofenvelope 2 by a plurality of projecting members 22.

The target-collector electrode assembly 10, inaccordance with thepresent invention, is supported from the main support means or targetcup electrode 10 by a vibrationisolating mount 24 which will now bedescribed in detail with respect to FIGS. 3 and 5. The target cupelectrode or main support means 10 includes a cylindrical wall portionprovided at its rearward end with an annular radially inwardly directedflange or wall member 26 forming a longitudinally facing transverseshoulder 28. Also rigidly secured to electrode 10 is a spaced annularwall member forming a shoulder 30 spaced opposite shoulder 28. Thetarget-collector electrode assembly 16 is rigidly clamped by screws 32(FIG. 5) to an outer ring 34. The outer ring 34 is in turn rigidlysecured by circumferentially spaced posts 36 to an annular inner ring ormounting member 38 extending in spaced relation between shoulders 28 and306 Openings 40 in flange 26am of sufiicient size to accommodate posts36 with clearance between the posts and flange 26. The annular mountingmember 38 is of somewhat flattened cross section forming faces 42, 44,as best shown in FIGURE 3, which confront opposing shoulders or surfaces28, 30 of target cup electrode 10.

The annular inner ring 38 is maintained in spaced axial relationshipbetween shoulders 28 and 30 on electrode by a plurality of pads 46 ofvibration-absorbent material compressed between the annular shoulders23, 30 and the opposing faces 42, 44. The pads 46 are desirably of sucha resilient quality as to permit slight axial move ment of the member38, and hence of the target-collector electrode assembly 20, as lowfrequencies below the resonant frequency of the target 12 or collectorelectrode 14, so as to avoid rupture or other injury to the target whenthe tube is subjected to such low frequency vibrations. However the padssubstantially completely attenuate higher frequency vibrations such aswould cause drumhead like vibrations and relative movement of the target12 and collector electrode 14 at frequencies equal to or above theirresonant frequency.

It is a particular feature of the invention that the pads 46 have notonly the desired mechanical properties for vibration and shockattenuation, but also are fully compatible with the requisites of thehigh vacuum environment in which the target-collector assembly isintended to operate. To this end the pads 46 are made of a materialhaving a sufficiently low vapor pressure of low capacity for occludedgases to avoid appreciable outgassing during tube operation. Stainlesssteel or Monel metal, for example, are suitable materials for the pads,and also glass, quartz and other non-metallic materials may be employedif sufliciently non-gassy. Moreover, we have found that the pads mayconsist of bundles of fibers of such nongassy material, partially feltedor worked into a resilient wool-like mass. Desirably and preferably,however, each pad may consist of a roll of metal mesh, of appropriatediameter such as to support the annular member 38 snugly and incompression between the shoulders 28, 30, 42, 44, the degree of suchcompression being suitable to give the desired damping characteristic atthe desired absorbing frequency. Such rolls may each be bent aroundmember 38, as preferably about outer edge 48, best shown in FIGURE 3,and permanently secured thereto as by welds 50 at the outer edge of themember 38.

To prevent any transverse movement of the target 12 or collectorelectrode 14, without interfering with the vibration damping effect ofthe pads 46 on axial movement of the target 12 or collector electrode14, annular member 38 is secured to the shoulder 30, and the member 34is secured to the flange 26, by a plurality of radially extendingflexible fingers 52, as best shown in FIGURE 4.

A vibration-isolating target mounting structure constructed as abovedescribed has been found to be extremely effective in preventingmovement of the target 12 relative to the collector electrode 14 atfrequencies such as have heretofore produced undesirable observableeffects in the picture or other image reproduced from the output signalof the tube. Moreover such a vibration-damping mount permits modestdamped movement of the target-collector electrode assembly at lowfrequencies below the frequency of resonance of the target 12 or mesh14, so as to preclude rupture or other damage to the target 12 or meshelectrode 14 when the tube is subject to such low frequency vibrations.Thus it will be evident that such a mounting arrangement as hereindescribed provides effective protection or ruggedization of the tubeagainst the deleterious effects of vibration and enables continuedoperation of the tube with desirable picture quality under extremelyadverse vibrational conditions.

It will be appreciated by those skilled in the art that the inventionmay be carried out in various ways and may take various forms andembodiments other than those illustrative embodiments heretoforedescribed. Accordingly it is to be understood that the scope of theinvention is not limited by the details of the foregoing description,but will be defined in the following claims.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In an electron discharge device, a main support having a pair ofspaced annular wall members, an electric charge storage target having asupporting frame, and means for supporting said target frame from saidmain support including an annular mounting member attached thereto andaxially spaced from said supporting frame and positioned in spacedrelationship between said pair of spaced annular members, andvibration-absorbent pads compressed between said annular mounting memberand said spaced annular wall members to dampen vibration of said annularmounting member.

In an evacuated electron discharge device of the image orthicon type, amain support therein having a pair of spaced transversely extendingconfronting shoulders defining an annular chamber, an electric chargestorage target having a supporting frame, and means for supporting saidtarget from said main support including an annular mounting memberattached to said target frame in axial spaced concentric relationshipand positioned between said confronting shoulders, a plurality of padsof vibration-adsorbent low vapor pressure material having a low capacityfor occluded gases compressed between said mounting member and saidconfronting shoulders, and means for restraining transverse movement ofsaid target relative to said main support.

3. In an evacuated electron discharge device of the image orthicon type,an annular target cup electrode therein forming a main support having apair of spaced annular transversely extending confronting shoulders, atransversely extending electric charge storage target having an annularsupporting frame, and means for supporting said target from said targetcup electrode including an annular mounting member rigidly secured tosaid target frame and extending between said confronting shoulders,vibration-absorbent pads of low vapor pressure material having a lowcapacity for occluded gases compressed between said mounting member andeach of said confronting shoulders to support said mounting memberagainst longitudinal movement, and a plurality of flexible fingersextending radially between said mounting member and said target cupelectrode for restraining transverse movement of said target relative tosaid target cup electrode.

4. In an evacuated electron discharge device of the type having a thintransversely extending membranelike charge storage target thereinmounted on an annular peripheral supporting frame, an electron collectorelectrode mounted on said supporting frame in spaced confrontingrelation with said target, and an annular main support for said targetand collector electrode, means for supporting said target and collectorelectrode assembly from said main support comprising a target mountingmember rigidly secured to said frame and defining a flat annular memberwith opposed surfaces, means on said main support forming a set ofoppositely facing transverse shoulders said flat annular member beingpositioned concentrically between said shoulders, and a plurality ofvibration absorbent pads of fibrous metallic material compressed betweenthe said shoulders and the said flat annular memher.

5. In an evacuated electron discharge device of the type having a thintransversely extending membrane-like charge storage target mounted on anannular peripheral supporting frame, an electron collector electrodemounted on said supporting frame in spaced confronting relation withsaid target, and a main support for said target and collector electrode,means for supporting said target and collector electrode assembly fromsaid main support comprising a target mounting member in the form of aflat annular member rigidly attached to said frame, means on said mainsupport forming a pair of oppositely facing transverse shoulders saidfiat annular member being positioned concentrically between and spacedfrom said transverse shoulders, a plurality of fibrous vibrationabsorbent pads of metallic material compressed between the said flatannular member and said shoulders, each of said pads comprising a rollof metal wire mesh looped over at least one edge of said annular memberto maintain said annular member in spaced axial relationship from saidshoulders for vibration damping thereof, and a plurality of flexiblefingers extending transversely between said mounting member and saidmain support for restraining transverse movement of said target relativeto said main support.

References Cited in the file of this patent UNITED STATES PATENTS2,400,332 Backman May 14, 1946 2,646,958 Coykendall July 28, 19532,661,437 Beckers Dec. 1, 1953 2,960,301 Roman Nov. 15, 1960 3,067,348Ochs Dec. 4, 1962

1. IN AN ELECTRON DISCHARGE DEVICE, A MAIN SUPPORT HAVING A PAIR OF SPACED ANNULAR WALL MEMBERS, AN ELECTRIC CHARGE STORAGE TARGET HAVING A SUPPORTING FRAME, AND MEANS FOR SUPPORTING SAID TARGET FRAME FROM SAID MAIN SUPPORT INCLUDING AN ANNULAR MOUNTING MEMBER ATTACHED THERETO AND AXIALLY SPACED FROM SAID SUPPORTING FRAME AND POSITIONED IN SPACED RELATIONSHIP BETWEEN SAID PAIR OF SPACED ANNULAR MEMBERS, AND VIBRATION-ABSORBENT PADS COMPRESSED BETWEEN SAID ANNULAR MOUNTING MEMBER AND SAID SPACED ANNULAR WALL MEMBERS TO DAMPEN VIBRATION OF SAID ANNULAR MOUNTING MEMBER. 